One‐pot Synthesis of Aromatic Fused 2,3‐Dihydroindanone by Tandem Pauson‐Khand/Michael/Henry Reaction

Abstract

The intermolecular Pauson-Khand reaction between 2-ethynylbenzaldehyde and ethylene promoted by dimethyl sulfide can be utilized to synthesize 2-(2-formylphenyl)cyclopentenone efficiently. This compound and its derivatives undergo a cascade process of Michael addition reaction followed by Henry reaction with nitromethane to construct substituted aromatic fused 2,3-dihydroindanones. Furthermore, direct one-pot synthesis of aromatic fused 2,3-dihydroindanones from 2-ethynylbenzaldehyde is achieved.

Synthetic Strategy Studies for a Concise Access to Functionalized Pyrano[4,3‐b]pyridin‐7‐ones: An Entry to Semi‐Rigid Analogs of Antihistamines

“…Experimental procedures and characterization data for new compounds or compounds made by a new method are listed below. For the experimental procedure and characterization data of the remaining compounds see references: Compounds 2, [17] 3, [6] 8, [12] 9, [12] 10, [18] 11 [19] were reported in literature, PP1a [4a] was reported without full characterization. Reagents were purchased as reagentgrade and used without further purification.…”

“…Yellow solid, 76 % yield. Mixture of 2 inseparable diasteroisomers 3/1; 1 H NMR (400 MHz, CDCl 3 ) of the major diastereoisomer: δ = 8.69 (d, 1H, J = 4.8 Hz, H 1 ), 7,49-7.27 (m, 11H, H 3, H8, 9,10,11,12,16,17,18,19,20 ), 7.08 (d, 1H, J = 7.5 Hz, H 2 ), 6.23 (s,1H, H 6 ), 5.50 (s, 1H, H 14 ); 13 C { 1 H} NMR (75 MHz, CDCl 3 ): 170.1 (C 13 ), 154.0 (C 5 ), 150.3 (C 1 ), 135.5 (C 4 ), 134.0 (C 3 ), 133.4 (C 7 or C 15 ), 131.1 (C 15 or C 7 ), 129,4-129,1-128,9-128,1-128,0-127.5 (C 8,9,10,11,12, 6,17,18,19,20 ), 122.6 (C 2 ), 79.9 (C 4 ), 54.9 (C 13 ) ppm; HRMS (ESI): m/z calcd. for C 20 H 16 NO 2 : 302.1176, found 302.1176 [M + H] + .…”

Domino Reactions through Recursive Anionic Cascades: The Advantageous Use of Nitronates

“…Starting from readily available o-alkynyl benzaldehydes 119, an interesting two-step indano-annulation sequence was described by Jiang and co-workers for synthesis of cyclopenta[a]naphthalenones 122 (Scheme 24). [43] Thus, initial Pauson-Khand reaction of 119 (R = H) with ethylene (to give 120, 71 %) followed by TDMP mediated recursive nitronate cyclization with nitromethane led to 121 which via in-situ aromatization led to indano-annulated products 122 (R = H, 84 %) quite efficiently. The overall sequence could also be implemented in a one-pot operation in an autoclave to directly deliver substituted cyclopenta[a]naphthalenones 122 in respectable yields (25-70 %).…”

One‐pot Two‐Step Cycloaddition Reaction for Convenient Synthesis of Polycyclic Spirooxindole‐fused [1,3]Oxazines

“…[1][2][3] Thus, spirooxindole has attracted much interests in synthetic and medical chemistry. [4][5][6][7][8][9] In many elegant synthetic methods for various spirooxindole systems, the multicomponent reactions or domino reactions have emerged as one of the efficient strategies, [10][11][12] which can provide diverse spirooxindoles in an operationally simple one-pot procedure from readily available chemical reagents. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] In the past few years, we have also developed several practical procedures for the synthesis of diverse spirooxindoles via multicomponent reactions by using isatins and its 3-methylene, 3-imino derivatives as the substrates.…”